1. Field of the Invention
This invention relates to a radiation image processing method and apparatus. This invention particularly relates to specifying of a portion, at which an abnormality occurs, and a cause of the abnormality in cases where the abnormality occurred during image processing.
2. Description of the Prior Art
Image processing techniques have heretofore been used, in which a radiation image having been recorded on photographic film is photoelectrically read out, an image signal representing the radiation image being thereby obtained, appropriate image processing is carried out on the image signal, and then a visible image is reproduced from the processed image signal. Also, radiation image processing systems, in which stimulable phosphors are utilized, have heretofore been used. Specifically, a radiation image of an object, such as a human body, is recorded on a sheet provided with a layer of the stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet). The stimulable phosphor sheet, on which the radiation image has been stored, is then exposed to stimulating rays, such as a laser beam, which cause it to emit light in proportion to the amount of energy stored thereon during its exposure to the radiation. The light emitted by the stimulable phosphor sheet, upon stimulation thereof, is photoelectrically detected and converted into an electric image signal. The image signal is then subjected to appropriate image processing and used for the reproduction of the radiation image of the object as a visible image on a recording material, such as photographic material, or on a display device, such as a cathode ray tube (CRT) display device. Such a radiation image processing system is disclosed in, for example, U.S. Pat. No. 4,258,264.
In the radiation image processing systems, various kinds of image processing are carried out such that a visible image suitable for use in making a diagnosis of an illness, or the like, can be obtained ultimately on photographic film, a CRT display device, or the like.
In general, in cases where image processing is carried out, it often occurs that an inappropriate visible image is obtained due to erroneous operations of image processing apparatuses, erroneous setting of image processing parameters, or the like. In such cases, ordinarily, the operator of the image processing apparatus investigates which step of the image processing was abnormal and why the abnormality occurred. The operator then eliminates the cause of the abnormality and again carries out the image processing.
In an image processing apparatus in which only one kind of simple image processing is carried out, it will not be very difficult to specify a portion, at which the abnormality occurred, or a cause of the abnormality. Also, in cases where complicated image processing is carried out, if the number of operations or settings carried out by the operator is small, a portion, at which an abnormality occurred, and a cause of the abnormality, can be specified by making reference to the operations or the settings. However, in cases where many kinds of image processing are carried out in accordance with many steps of operations or many setting parameters as in the aforesaid radiation image processing systems, it is difficult to ascertain a portion, at which the abnormality, occurred, and a cause of the abnormality by merely seeing an inappropriate visible image, which is Age obtained ultimately. Therefore, in the past, considerable time and labor were required to specify a portion, at which the abnormality occurred, or a cause of the abnormality by, for example, again carrying out a plurality of processes of the image processing one after another.
The primary object of the present invention is to provide a radiation image processing method wherein, in cases where an abnormality occurred during image processing carried out on a radiation image, a process, in which the abnormality occurred, is capable of being discriminated quickly, and a cause of the abnormality is capable of being specified quickly.
Another object of the present invention is to provide an apparatus for carrying out the radiation image processing method.
The present invention provides a first radiation image processing method for carrying out image processing, which is constituted of a plurality of processes, on a radiation image signal,
wherein an intermediate image signal obtained in at least one process is stored, which is among the processes other than a last process in the plurality of the processes constituting the image processing, the intermediate image signal being stored on a predetermined storage medium.
In the first radiation image processing method in accordance with the present invention, the storing of the intermediate image signal on the storage medium should preferably be carried out by repeating overwriting on a predetermined storage area of the storage medium. Also, the overwriting on the predetermined storage area should preferably be ceased and an intermediate image signal, which has been stored in the storage area, should preferably be retained in accordance with an instruction, which is given by an operator, or a signal, which represents the occurrence of abnormality in a preceding process.
The present invention also provides a second radiation image processing method for carrying out image processing, which is constituted of a plurality of processes, on a radiation image signal,
wherein an intermediate image signal having been obtained in a process is stored, which is among the plurality of the processes constituting the image processing and in which an abnormality occurred, the intermediate image signal being stored on a predetermined storage medium.
The present invention further provides an apparatus for carrying out processing in accordance with the aforesaid first radiation image processing method. Specifically, the present invention further provides a first radiation image processing apparatus, comprising:
i) a plurality of image processing means for successively carrying out different kinds of image processing on a radiation image signal, and
ii) a storage means for storing an intermediate image signal obtained from at least one image processing means, which is among the plurality of the image processing means and carries out image processing other than last image processing.
In the first radiation image processing apparatus in accordance with the present invention, the storage means should preferably store the intermediate image signal by repeating overwriting on a predetermined storage area. Also, the storage means should preferably cease the overwriting on the predetermined storage area and should preferably retain an intermediate image signal, which has been stored in the storage area, in accordance with an instruction, which is given by an operator, or a signal, which represents the occurrence of an abnormality in a preceding process.
The present invention still further provides a second radiation image processing apparatus, comprising:
i) a plurality of image processing means for successively carrying out different kinds of image processing on a radiation image signal, and
ii) a storage means for storing an intermediate image signal having been obtained from an image processing means, which is among the plurality of the image processing means and in which the abnormality occurred.
The term xe2x80x9clast processxe2x80x9d or the term xe2x80x9clast image processingxe2x80x9d as used herein means the process or the image processing such that an image signal obtained at the time, at which the process or the image processing is finished, may serve as the image signal fed out from the radiation image processing apparatus.
Also, the term xe2x80x9cintermediate image signal obtained (or having been obtained) in a processxe2x80x9d or the term xe2x80x9cintermediate image signal obtained (or having been obtained) from image processing meansxe2x80x9d as used herein means the image signal, which is obtained when the processing to be carried out in the process or the image processing means has been carried out, and the image signal, which is formed when the processing to be carried out in the process or the image processing means has been interrupted due to some cause. The term xe2x80x9cintermediate image signal obtained (or having been obtained) in a processxe2x80x9d or the term xe2x80x9cintermediate image signal obtained (or having been obtained) from image processing meansxe2x80x9d as used herein further means the image signal, which occurs when, even though the image signal has passed through the process or the image processing means, no processing has been carried out on the image signal, and the same image signal as that at the beginning of the process (or the same image signal as that having been fed into the image processing means) is obtained.
Further, the term xe2x80x9cpredetermined storage mediumxe2x80x9d as used herein means a storage device, such as a hard disk or a memory. In the radiation image processing method and apparatus in accordance with the present invention, as described above, the storing of the intermediate image signal on the storage medium may be carried out by repeating overwriting on a predetermined storage area. Specifically, a storage area for a single image signal may be prepared, and the intermediate image signal may always be written into the storage area when the intermediate image signal is to be stored. Alternatively, for example, a storage area for a single image signal may be prepared for each of the processes, and the storage areas for the respective processes may be used such that, as for one radiation image, all of the obtained intermediate image signals may remain unerased without the overwriting being carried out, and such that, when the next radiation image is processed, new intermediate image signals are overwritten upon the previously stored intermediate image signals. Specifically, the term xe2x80x9crepeating overwriting on a predetermined storage areaxe2x80x9d as used herein does not necessarily mean that the overwriting is carried out each time an intermediate image signal is stored, and means that a certain limited storage area is subjected to the overwriting and is used repeatedly.
In the radiation image processing method and apparatus in accordance with the present invention, as described above, in accordance with an instruction given by an operator or a signal representing the occurrence of abnormality in a preceding process, the overwriting on the predetermined storage area may be ceased, and an intermediate image signal, which has been stored in the storage area, may be retained. For such purposes, for example, the processing may be interrupted immediately such that the overwriting may not be carried out. Alternatively, immediately before the overwriting is begun, the processing may be interrupted temporarily, and the intermediate image signal, which has been stored in the storage area, may be saved to a different area. As another alternative, the overwriting on the storage area may not be carried out any more, and the next storage and those that follow may be carried out on different storage areas.
The term xe2x80x9cprocessxe2x80x9d as used herein means the minimum processing unit, which the designer considers to be necessary when a portion, where an abnormality occurred, is specified. Therefore, even for image processing apparatuses in which the same image processing is carried out, the processes are not necessarily determined uniquely and may be defined in various different ways. For example, in an operation for detecting a radiation image signal from a radiation image, each of the scanning along a main scanning direction and the scanning along a sub-scanning direction may be taken as a single process, and the storing of the intermediate image signal may thereby be carried out. In such cases, when a portion, at which an abnormality occurred, is specified, it can be discriminated whether the abnormality occurred during the scanning along the main scanning direction or during the scanning along the sub-scanning direction. However, in cases where the combination of the scanning along the main scanning direction and the scanning along the sub-scanning direction is taken as a single process, when a portion, at which an abnormality occurred, is specified, it can be found only that the abnormality occurred during the operation for detecting the radiation image signal from the radiation image. Also, the term xe2x80x9cimage processing meansxe2x80x9d as used herein does not necessarily correspond to a single set of hardware functions or a single program, and means a conceptional image processing means.
The term xe2x80x9cabnormalityxe2x80x9d as used herein means an error, warning, or the like. When abnormality occurs, the processing may be interrupted. Also, when abnormality occurred, the processing may not be interrupted and may be continued.
With the first radiation image processing method and the first radiation image processing apparatus in accordance with the present invention, wherein image processing, which is constituted of a plurality of processes, is carried out on the radiation image signal, the intermediate image signal obtained in each of the processes is stored. Therefore, the progress of the image processing remains such that it can be watched. In cases where an abnormal output is obtained from the image processing, the intermediate image signal can be investigated, and the specifying of a portion, at which abnormality occurred, and investigation of the cause of the abnormality can thus be carried out quickly.
Also, in cases where the intermediate image signal is stored, a certain limited storage area may be used repeatedly such that an intermediate image signal, which will later become necessary for specifying a portion, where an abnormality occurred, may not be erased by the overwriting, and such that the other unnecessary intermediate image signals may be erased by the overwriting. In this manner, the storage capacity of the storage medium to be used can be kept small.
With the second radiation image processing method and the second radiation image processing apparatus in accordance with the present invention, in cases where a process has been finished normally, the storing of the intermediate image signal is not carried out. Only when an abnormality has occurred or an instruction has been given by the operator, the intermediate image signal is stored. Therefore, the information necessary for specifying a portion, at which the abnormality occurred, and the cause of the abnormality can be kept by using only a small storage capacity of the storage medium.